//-----------------------------------------------------------------------------
// Copyright (c) 2012 GarageGames, LLC
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//-----------------------------------------------------------------------------

#pragma once

#include "globals.h"
#include <stdlib.h>
#include <math.h>
#include <vector>
#include <assert.h>
#include <cstring> // for memset


namespace TriListOpt
{
	typedef unsigned U32;
	typedef int S32;
	typedef float F32;
	typedef unsigned dsize_t;
	typedef U32 IndexType;

	const U32 MaxSizeVertexCache = 32;

	struct VertData
	{
		S32 cachePosition;
		F32 score;
		U32 numReferences;
		U32 numUnaddedReferences;
		S32 *triIndex;

		VertData() : cachePosition(-1), score(0.0f), numReferences(0), numUnaddedReferences(0), triIndex(NULL) {}
		~VertData() { delete [] triIndex; }
	};

	struct TriData
	{
		bool isInList;
		F32 score;
		U32 vertIdx[3];

		TriData() : isInList(false), score(0.0f) { memset(vertIdx, 0, sizeof(vertIdx)); }
	};

	class LRUCacheModel
	{
		struct LRUCacheEntry
		{
			LRUCacheEntry *next;
			U32 vIdx;
			VertData *vData;

			LRUCacheEntry() : next(NULL), vIdx(0), vData(NULL) {}
		};

		LRUCacheEntry *mCacheHead;

	public:
		LRUCacheModel() : mCacheHead(NULL) {}
		~LRUCacheModel();
		void enforceSize(const dsize_t maxSize, std::vector<U32> &outTrisToUpdate);
		void useVertex(const U32 vIdx, VertData *vData);
		S32 getCachePosition(const U32 vIdx);
	};


	/// This method will look at the index buffer for a triangle list, and generate
	/// a new index buffer which is optimized using Tom Forsyth's paper:
	/// "Linear-Speed Vertex Cache Optimization"
	/// http://home.comcast.net/~tom_forsyth/papers/fast_vert_cache_opt.html
	/// @param numVerts Number of vertices indexed by the 'indices'
	/// @param numIndices Number of elements in both 'indices' and 'outIndices'
	/// @param indices Input index buffer
	/// @param outIndices Output index buffer
	///
	/// @note Both 'indices' and 'outIndices' can point to the same memory.
	void OptimizeTriangleOrdering(const dsize_t numVerts, const dsize_t numIndices, const U32 *indices, IndexType *outIndices);

	namespace FindVertexScore
	{
		const F32 CacheDecayPower = 1.5f;
		const F32 LastTriScore = 0.75f;
		const F32 ValenceBoostScale = 2.0f;
		const F32 ValenceBoostPower = 0.5f;

		F32 score(const VertData &vertexData);
	}
}

